C14 Dating is unique in that, as its halflife is 5,730 years, it can be used to date things relatively accurately in the recent past, as long as it is a)organic and b)dead. However, subsequent to 1950 and the nuclear testing binge the world went on, assigning dates has been made somewhat trickier, as various parts of the globe were exposed to different amounts of fallout. To circumvent this uncertainty, the SCP states a minimum age, rather than an exact age. I'm not about to go running the calculations to figure out the probable error and all that other crap.

If you want to learn more about C14 dating, you can go read about it at the other wiki.

I like it, though I think it could maybe use a little something extra that might push it from weird to interesting (strange bio matter is a little overdone).
Also, for a hole in the mountains that nothing comes out of, you could have a smaller containment area easily. A 20km radius is about 450 square miles. It's in the mountains, just block off nearby peaks, or build a wall… way easier

I hate to judge an SCP based on something other than individual merit, but I really don't see the point of this remaining on the site along with SCP-1437, which is a far more interesting version of a similar idea. Downvoted